This invention relates to a novel hazardous waste removal system. More specifically, this invention relates to a system for removal of hazardous waste, such as asbestos, from tubular conduits and the like.
In the past, asbestos containing materials have been used to insulate pipes and valves in chemical processing plants, commercial and residential buildings, and in other installations requiring insulation and fire resistant coverings. It has now been documented that exposure to asbestos may lead to cancer. Cancer-related maladies linked to asbestos are generally classified into five different categories, including asbestosis, a type of pulmonary disease caused by inhalation of asbestos-containing dust; pleural disease, which relates to changes in the pleura (the membranes enveloping the lungs and pleural cavity) caused by inhalation of the asbestos fibers; lung cancer; mesothelioma, a form of cancer of the pleural and peritoneal cavities; and other cancers such as laryngeal cancer and cancer of the gastrointestinal tract. Since the discovery of the cancer-causing propensities of asbestos-containing materials, efforts have been made to eliminate sources of asbestos fiber pollution of ambient air.
Asbestos, a fibrous form of magnesium and calcium silicate ore, is a friable material which may release microscopic fibers into the air. This presents a health hazard to workers responsible for removing asbestos-containing insulation materials. Consequently, elaborate provisions and regulations have been enacted to control the removal of these materials to minimize risk to workmen.
The use of protective bag assemblies for isolating asbestos-coated conduits and/or protective clothing, including face masks to prevent inhalation of air borne fibers, have become mandatory accessories for workmen involved in removing asbestos-containing insulation.
In order to comply with the established regulations, assemblies have been devised to prevent the propagation of these contaminants into the atmosphere. In this connection, numerous waste removal systems have been designed utilizing a glove bag concept. One such glove bag removal system includes a detachable bag which sealingly encompasses a section of a pipe to be cleaned. A pair of specially shaped flaps are secured to a longitudinal axis of the pipe to form a circumscribing sleeve portion about the pipe. The bag also includes an internal tool pouch and inwardly extending armholes to permit a user to strip the fibrous material from the pipe while remaining isolated from the asbestos-containing materials. A lower portion of the ba collects the removed contaminant material in a separate collection compartment, and the collection compartment is then sealed and removed from a reusable upper portion of the bag.
The configuration described above is problematic, however, because airborne fibers may remain in the reusable upper portion of the bag and escape into the ambient air when the collection compartment is detached from the upper portion of the assembly, exposing the worker to the contaminant.
In order to prevent escape of particles from a glove bag, a more recent improved glove bag included an inlet for a vacuum probe which was inserted into the bag to maintain the interior of the bag at a negative pressure during removal of the waste material. The negative pressure gradient ensured that the airborne contaminants were captured and removed by the vacuum probe. Such glove bags also typically included one or more openings for water spray lines or water nozzles as an extra safety precaution for making the material less friable by wetting it down.
Though the use of a vacuum reduced the risk of leakage of the fibrous contaminant material into the air, the vacuum also introduced problems associated with working in a negative pressure area. More specifically, the bag was drawn inward and, thus, restricted the working area inside the bag so that an operator has little room to manipulate tools used to remove the material from the pipe. Moreover, the negative pressure drew the opposite sides of the bag together, closing off passage to a lower portion of the bag, thereby preventing contaminant material from accumulating in the lower portion of the bag. Also, a sudden loss in negative pressure permitted airborne contaminant fibers to potentially escape from the glove bag through water inlet openings.
To permit passage of the contaminant material to a collection compartment, various cages constructed of metal or other suitable rigid materials were used in conjunction with the glove bag. Typically, the cage was mounted about the pipe, and, when negative pressure was introduced into the bag, the cage prevented the opposing sides of the bag from collapsing together. One embodiment of such an arrangement included a metal frame extending below a conduit and supporting a rigid cylindrical cage. However, these metal frame and cage assemblies tended to be cumbersome to assemble. Further, such assemblies restricted access to areas of the pipe obstructed by the frame, and the frame limited the mobility of the glove portions of the bag. Moreover, the cage assembly and associated frame were expensive and, thus, not cost effective.
The difficulties suggested in the preceding are not intended to be exhaustive but rather are among many which may tend to reduce user satisfaction with prior hazardous waste removal assemblies. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that hazardous waste removal assemblies appearing in the past will admit to worthwhile improvement.